Yes ma'am! The mother and son who both went to war in Afghanistan

And like most young men, they get in touch sporadically – usually through a garbled telephone call or a hastily written email.

As all three brothers are in the Armed Forces, Joan knows they have a good excuse.

Theatre: Captain Joan Welsh in her role as a theatre nurse at Camp Bastion in southern Helmand Province, Afghanistan

In the age-old tradition of military families, she just ‘got on with it’ until the day she opened an email from her middle son Christopher in Afghanistan and read the dreaded words: ‘Mum, I’ve been in an accident.’

With her heart in her mouth, she read on: ‘Our helicopter crashed. 'It was pretty terrifying and the aircraft is destroyed.

'But I’m OK, don’t worry. It was a lucky escape.’

Proud: Joan in her mess uniform

On the surface, Joan’s story is similar to that of thousands of military mothers, wives and girlfriends.

Except that she wasn’t waiting for news thousands of miles away in Britain.

She was a few hundred miles away from her son, serving as a theatre nurse at Camp Bastion, the British base in southern Helmand Province.

Fighting back tears, she reread the email.

She only had time to reply ‘Thank God you’re OK, xxx Mum’ before her strict 20-minute computer allocation was up.

Every day she helped treat soldiers with the most appalling injuries – missing limbs, brain damage, shrapnel wounds – and every day she prayed Christopher would not be rushed through the doors of her makeshift field hospital.

While she shuddered at her first-hand knowledge of what might have been, Joan reflected on the extraordinary turn her life has taken.

Indeed, her situation is believed to be unique.

While it is quite common for fathers and sons to be deployed simultaneously to a war zone, Joan and Christopher are thought to be the first mother and son to have served their country together.

Christopher, 22, serves as a senior aircraftman in the RAF’s tactical communications unit in Afghanistan.

Thomas, 20, a leading aircraftman, based at RAF Odiham, Hampshire, is due to be sent there later this year, while her oldest son Peter, 25, is currently a senior RAF aircraftman with a search-and-rescue team on Anglesey.

But it is Joan – a Captain in the Liverpool 208 Unit of the Territorial Army – who has the highest rank.

‘I never thought I would end up being a nurse in a war zone,’ she says.

‘To go from leading a relatively normal life working for the NHS to serving in Afghanistan with my son has just been an extraordinary experience.

Ordeal: Christopher was caught up in a helicopter crash while serving in Afghanistan

'I didn’t think any of my children would join the Forces, let alone me.’

Joan’s life was turned upside-down seven years ago. She believed she was happily married and was content bringing up her three teenage boys in the family home in Chester while working as a senior operating nursing sister at Clatterbridge Hospital on the Wirral.

But in January 2001 her 20-year marriage came to an abrupt end.

‘It was my husband’s choice to leave and I was devastated,’ said Joan, who turns 50 next year.

‘In retrospect, we had grown apart and separating was the right thing for us to do, but I couldn’t see it at the time.’

Joan had no real social life and her sons, who had been the centre of her world for many years, were fast growing up.

She realised she needed to make a fresh start in life and within months had followed a friend’s advice and signed up for the Territorial Army.

She made a whole new group of friends – ‘her extended family’ – and started enjoying life again.

‘The whole experience was fresh and exciting,’ she says.

At the time, of course, the prospect of war seemed remote.

But in September 2001, the twin towers of the World Trade Centre were attacked.

For Joan, training in the TA became more focused and intense.

But it wasn’t until 2006 that her entire 80-strong TA unit was told it would take over the running of the military hospital at Camp Bastion for four months from June 2007.

‘It was a terrifying moment,’ says Joan. ‘I had always known there was a chance we could be called up, but part of me didn’t really think it would ever happen.'

To make things even harder, Joan had also recently embarked on a new relationship.

She and John, 56, a London barrister, divided their time between their two homes in London and Chester, all too aware that soon Joan would be leaving for Afghanistan.

By this stage, two of Joan’s sons had already joined the Forces, despite there being no previous family link with the military – while her youngest, Tom, was still at home, studying for his A-levels.

‘When I told them I was going, they couldn’t believe it,’ she recalls. ‘But they were very supportive and proud, despite being worried.

‘It was only Tom who didn’t want me to go.

'We were very close as we had lived on our own for a few years and he kept saying, “Please don’t go.”

‘I felt guilty but knew he had his father and brothers to support him and the truth is I wanted to go.

'Despite being scared, I wanted to use my training and experience.’

Shortly before her departure, Joan received another jolt when she was told that Christopher would also be deployed to Afghanistan, leaving just two weeks after her.

‘We couldn’t believe it,’ she says. ‘Obviously, I was worried for him but what could I say?

‘I knew we were both going to have an extraordinary experience and just tried to stay strong and positive.’

But Joan’s bravado evaporated as her unit gathered at RAF Brize Norton in Oxfordshire to board the plane to Afghanistan.

Christopher had been given permission to wave her off and as they hugged each other farewell, the enormity of what they were both doing suddenly hit her.

‘I couldn’t stop crying, which is not like me at all,’ she says. ‘It was very hard to get on that plane.’

In Camp Bastion, however, there was no time for sentiment.

Using her experience as a theatre sister, she worked side-by-side with the doctors during life-saving operations, treating soldiers who had been caught in explosions or vehicle crashes, or wounded in ferocious fighting with the Taliban.

The tented field hospital is air-conditioned, with two operating theatres and decent equipment. But the hours are punishing.

Two teams worked day and night on a rota system, often dealing with multiple casualties.

‘There was one four-day period when we worked constantly, only able to snatch a few minutes to eat or an hour here and there to sleep,’ Joan said.

‘We didn’t have a single day off in the four months of our tour of duty.’

As well as looking after British and Coalition soldiers, they treated captured Taliban fighters and civilians who were caught up in the action.

Sometimes these would be young children and babies who the medics fought desperately to save.

Joan says: ‘I am immensely proud of what we achieved. The standard of care we gave the casualties could not have been bettered.

‘Of course, we saw some horrific injuries – young soldiers, often teenagers, who needed multiple amputations, or had suffered brain damage.

‘You can’t help wondering what sort of lives they were going to lead from then on.

‘But you can’t get upset. If you did, you’d be no use to anyone.’

Not surprisingly, Joan worried about Christopher, who moved around Helmand province with his unit and with whom she had very little contact.

But she made herself stop.

'I couldn’t keep thinking it was him every time a casualty alert came through,’ she says.

‘I forced it to the back of my mind or I wouldn’t have been able to work.’

She also missed her two other sons at home, and, of course, her partner John.

‘The most difficult part is not being able to communicate,’ she says.

‘We were allowed only 20 minutes on the computers every couple of days and occasional phone calls.

‘But whenever there was an incident, someone injured or killed, which was quite often, there was a complete communications crackdown.

'No one could contact anyone until the next-of-kin had been informed, which sometimes took days.’

Despite the difficulties, Joan and her comrades tried to make the best of their time on the base.

Most mornings at 5.30am, before the temperature soared to 122F (50C), they would run the four-and-a-half miles around the camp’s perimeter to keep fit.

Some evenings, under the brilliant stars, they would watch a film projected on to a white sheet blowing in the dry dusty wind.

It was near the end of her four-month stint when the email came through from Christopher about his accident.

‘That was one of the worst times,’ Joan recalls.

‘After the crash, his commanding officers told him to ring home to let his next-of-kin know what had happened.

'They couldn’t believe it when he told them I wasn’t at home but in Camp Bastion.’

Joan flew out of Afghanistan in October last year, followed two weeks later by Christopher.

Back in London, Joan found civilian life strange.

‘I couldn’t get my head around the fact that no one knew I had been out there.

'I just wanted to tell everyone, even strangers on the street, what I’d done.’

When Christopher arrived home, they had an emotional reunion.

‘It was so good to see him,’ she says. ‘We both know what it’s like out there, we can relate to each other.

‘I know quite a few dads and sons go to war at the same time but I think we were the first mum and son – and that makes me very proud.’

Since her return, Joan has graduated with an honours degree in Critical Care nursing.

She is also engaged to John and has moved to London to be with him.

But her life as a military mum is far from over. Tom is going to Afghanistan later this year.

Joan feels her time in Helmand will help her deal with Tom’s deployment.

‘Other mums don’t know what it’s like out there, but I do,’ she says.

‘I know where he will be going and what he’ll be doing. I know where he will be treated if, God forbid, he gets injured.

‘Obviously I am worried about him but it is his choice to go, and, having been there, it makes it easier for me to accept that.’

Joan is now happy not to have anything more to do with war herself.

‘I don’t want to go back out there – it was an incredible experience but I’m happy being in London, leading a normal life again,’ she says.

'Of course I can’t help but think about it.

‘When I watch the news and hear about a casualty, I imagine the doctors and nurses out there getting the alert and battling to save lives.

'I know what they are going through.

‘It has changed me – I have to confess that I am a little less patient now when people moan about trivial things.

‘Having seen what I did in Afghanistan I am so much more aware of how lucky most of us are.’